The dilemma of consistency in technology architecture

As one of the key elements of enterprise architecture, the "platform" or "technology" architecture is about what kind of software and hardware tools and systems to use across the whole organization.

One can imagine that there are ways of maintaining a strategy of having a "buying list" of these systems for an enterprise. Historically or even nowadays, large enterprises tend to put a lot of efforts on maintaining the "open system" concept. Here the "open system" concept means that an enterprise use software systems that accepts and enables  interoperability, portability and open software standards. But in reality, not all software vendors give full-support to open standards and using systems from various technology and vendor background means extra cost of ownership to the IT managers. Thus, the following two phenomenas show the general dilemma of most enterprises towards technology choices.

• Due to business and economical requirements, different departments are becoming more and more vendor dependent in spite of the enterprise-wide strategy of supporting open system concept. 
• Although most departments are using standard products, no matter if they come from a single vendor a or limit group of them, different local units still choose to use packaged solutions (often called appliances)  in situations where they often find it hard (or expensive) to use the standard tools.

So should an architect put all her/his effort to ensure the consistency of the usage of standard tools?

Although consistency is definitely a personal virtue, it is absolutely not expandable to IT architecture. Instead of wasting all the effort to keeping the consistency, it is more useful to focus on maintaining the architectural strategy in a timely manner and getting ready to accept new ideas and changes from time to time.

In terms of integration of different systems, it is always important to consider a set of protocols in the infrastructure when adding new items in the buying list.

1. Middlewares and gateways that enable the integration;
2. Communication protocols such as web services
3. Information brokers, such as those that transform the data-types, char-sets (ASCII to EBCDC), or XML-based transformation
4. BPM tools that cope with processes at various frequencies;
5. Event and alert management tools;
6. Message-based systems, i.e., solutions that can keep messages for various systems. 
7. Application-oriented adapters that support integration of applications with other existing solutions.